Use of sunlight energy to eliminate pollutants in waste water from chemical laboratories

Abstract

Introduction. The use of sunlight energy to eliminate pollutants in waste water, by the use of an appropriate catalyst, uses the sunlight that arrives directly to the Earth to produce several chemical reactions which allow the elimination of organic compounds in the water from urban, industrial and agropecuary effluents and change the oxidation state of heavy metals in a way that they pass from being soluble to an insoluble form. Objective. To evaluate the water degradation with methylene blue used to analyze some tests in chemicals laboratories by the use of a photosensitizer, using sunlight. Materials and methods. The degradation and mineralization of waste water with methylene blue by means of the sunlight was made. Different tests were made with the hydrogen peroxide, titanium dioxide and air combination. The degradation of this waste water was followed by the color reduction at a 650nm wavelength and the COD technique was used for the mineralization. Results. The optimal concentration of photo catalyst and oxidation agent for the degradation of waste water with methylene blue in a 30 mg/L concentration rate in the water found in this research work are: L20 mg/L of TiO2 and 2 mL H2O2/L with an air injection. Conclusion. Very good results in color degradation and lower mineralization percentages were found in an eight hour time of sunlight irradiation.